Some 2.6 billion people in the world, mainly in Africa and Asia, lack access to basic sanitation, increasing the risk of diarrhoea and other diseases fatal to children, says a UN report.

Some 2.6 billion people in the world, mainly in Africa and Asia, lack access to basic sanitation, increasing the risk of diarrhoea and other diseases fatal to children, said a UN report released on Thursday.

Unicef, the UN children's fund, in a study on water and sanitation in developing nations, concluded that UN goals could be met on clean water, especially in urban areas, but the same was not true for access to the crudest of toilets.

The report, Progress for Children, surveyed available clean water and sanitation facilities from 1990 to 2004 and calculated which countries could meet goals set at a UN Millennium summit in 2000.

These include cutting in half by 2015 the proportion of people without safe drinking water and basic sanitation. The largest gains were in Asia, especially in India and China.

But the report said the majority of people in both countries still have no adequate sanitation, especially in rural areas. In 1990, only about three per cent of the rural population in India had access to improved sanitation.

“Considerable progress has been made and approximately a third of India’s population today has access to sanitation facilities,” the report said. "Despite commendable progress, an estimated 425 million children under the age of 18 still do not have access to an improved water supply and over 980 million do not have access to adequate sanitation, said Anne Veneman, Unicef's executive director and a former US secretary of agriculture.

Overall, about 1.2 billion people, or an increase from 78 per cent in 1990 to 83 per cent in 2004, had access to drinking water, a figure that would meet the Millennium goals.

The lack of access to water is especially acute in sub-Saharan Africa, which represents about 11 per cent of the world's population but almost a third of all people without access to safe drinking water.